The invention relates to a belt band conveyor, particularly a curved belt conveyor, having an endless transport belt that is guided over deflection rollers. Attached to the transport belts, is a guide element that projects beyond the belt plane. This guide element can be handled separately before it is attached to the transport belt, and which moves along as the transport belt moves. The guide element has guide surfaces, which extend in the transport direction of the transport belt. There are also running surfaces that are inclined relative to the belt plane and which roll off from rotating guide rollers, to compensate for lateral forces that occur crosswise to the transport direction of the transport belt.
A curved belt conveyor has become known from German Patent DE 42 13 035 A1, which relates to a corresponding U.S. Pat. No. 5,332,083 the disclosure of which is hereby incorporated herein by reference. This reference which discloses a circulating endless transport belt which is connected with an edge bead that runs along its outside edge. This belt is continuous, is inseparably connected with it, and circulates along with it. Several guide rollers are elastically pressed against this flank, which points towards the center of the curve, to compensate for the longitudinal and traverse forces that occur as a result of the curve progression. This occurs even in the case of a severely distorted curve, and in the case of significant level differences between the deflection rollers at the end, with low friction wear.
German Patent DE 38 26 953 A1 discloses a similar curved belt conveyor having a transport belt that is deflected by way of cone-shaped support rollers, which has a continuous, co-circulating, bead-shaped edge strip. The edge strip, again, is guided between guide rollers that have inclined running surfaces, to compensate for the centripetal forces that occur during operation.
A similar belt band conveyor has become known from German reference DE 198 54 327 A1, which has a corresponding U.S. Pat. No. 6,564,931, the disclosure of which is hereby incorporated herein by reference. There, a toothed belt component of a toothed belt that is continuous and circulates with the transport belt is provided to transfer the force of the drive forces from a gear crown to the transport belt. The toothed belt component has a bead strip on its ends that point radially inward, in each instance, which is continuous over the length of the transport belt. Again, inclined running surfaces of guide rollers engage on the bead to be able to absorb the forces directed to he inside radius of belt curves and to achieve secure guidance of the transport belt.
German reference DE 199 53 691 A1 discloses a further development of the belt band conveyor described above, which relates to a belt tensioning device. There, a continuous toothed belt is attached to the bottom of the transport belt, moving with it, and a continuous profile that lies opposite is attached to the top of the belt. The profile has an elevation that faces away from the edge region of the transport belt, which again serves for contact of guide rollers. To secure the position of the transport belt when the belt starts up under stress, and to prevent the teeth of the gear wheel of the drive roller and the teeth of the toothed belt from getting out of engagement, there are several ball bearings, which contact the profile at the top of the transport belt.
Another system of a curved belt conveyor has become known from German reference DE 198 05 204 A1. There, a continuous holder strip, disposed radially on the outside, is attached on the inside of a circulating transport belt. Slide sleeves that can rotate about axles of rotation arranged perpendicular to the transport belt plane are attached to the holder strip, wherein these are guided in guide grooves of guide rails, with a positive lock.
In the case of all of the aforementioned belt band conveyors, the guide strips are stretched at the deflection in the region of the deflection rollers. Therefore, a material that permits constant expansions at the deflection must be selected. This in turn has the result that a soft, i.e. flexible material must be selected. The stresses that occur have the result that the lifetime of the guide strips is short. In the case of high speeds and small deflections, such guide strips, known from the state of the art, fail after a correspondingly short period of use.
Alternative solutions relate to curved belt conveyors in which guide rollers that circulate with the belt are attached, which are guided in locally fixed guides. Such a curved belt conveyor has become known from EP 0 980 462 B1. This discloses several co-circulating rollers on the endless transport belt of this conveyor, to guide it and to compensate for radial forces that are directed towards the inside of the curve. In this case, the axles of rotation of these rollers are attached to the transport belt via attachment means that project through openings in the transport belt. As the transport belt circulates, the running surfaces of the co-circulating rollers run along either only vertical or vertical and horizontal stationary guide surfaces of a support frame.
Similar curved belt conveyors have become known from U.S. Pat. No. 5,332,082 and NL-A-8702617.
With these solution variants, however, permanent excess stress in the region of the roller attachment to the belt can occur, in connection with the risk of canting and/or tearing in this region, so that these alternatives also cannot guarantee long life. However, a long life of the belt is particularly important, particularly in the case of belt curves, because as a rule, the belt is the most expensive element, and the replacement part is accordingly expensive. Another disadvantage in the case of these solution alternatives is the development of great noise at high circulation speeds.
A slat conveyor belt, i.e. a slat conveyor, has become known from German reference DE 103 22 216 A1 and from German Patent DE 23 23 601 C2 which relates to a corresponding U.S. Patent, the disclosure of which is hereby incorporated herein by reference. This disclosure of the slat conveyor belt comprises two belts or bands that circulate at a distance from one another, to which slats are attached, arranged in each instance crosswise to the transport direction. Guide element having guide surfaces extending in the transport direction of the transport belt, on which running surfaces inclined relative to the belt plane would roll off from rotating guide rollers as the transport belt circulates, so that crosswise forces that act on the transport belt, crosswise to its transport direction, can be or are compensated, are not provided there.